This invention relates to semiconductor devices comprising P-type quaternary ZnMgSSe layers.
This invention relates especially to semiconductor laser structures formed from II-VI materials having P-type quaternary ZnMgSSe layers that emit light in the blue-green region and laser diodes comprising such structures.
This invention relates especially to laser structures and laser diodes having an n-type semiconductor substrate, a p-type quaternary ZnMgSSe cladding layer and a ternary ZnCdSe active layer.
Laser structures of this type are described in European Patent Application 0 605 051 A1 published Jun. 7, 1994 and in Gaines et al. U.S. Pat. No. 5,363,395, the contents of which are hereby incorporated by references.
As shown in the above-mentioned references, the dopant concentration in the p-type cladding layer is not greater than 2.times.10.sup.17 cm.sup.-3. It has also been found that the mobilities of the dopants therein are not greater than 4 cm..sup.2 /volt. sec.
As a result of this rather low dopant concentration and mobility, resistant layers are formed in this cladding layer resulting in a decrease of the conductivity of this cladding layer and requiring an increase in the operating voltage of the laser structure.